1. Field of the Invention
The present invention relates to an electronic image forming apparatus and more particularly, to a toner cartridge for use in an electronic image forming apparatus, which effectively prevents leakage of toner.
2. Description of the Related Art
FIGS. 1 and 2 show a toner cartridge according to the prior art. According to this design, the toner cartridge 1 is comprised of a housing 2 and an inner tube 3. The housing 2 comprises a tubular portion 4 and a receiving portion 5 for holding toner. The tubular portion 4 is a cylindrical member. The inner tube 3 is rotatably mounted in the tubular portion 4. The receiving portion 5 has an irregular shape fitting the holder of toner cartridge. The inner tube 3 has a slot 6 at the bottom side for communicating the outlet 7 of the housing 2, and an open-space portion 8 at the top side for communication between the inside space of the inner tube 3 and the inside space of the housing 2.
Toner is allowed to pass from the housing 2 to the inner tube 3 through the open-space portion 8. When rotated the inner tube 3 to the open position as shown in FIG. 1, the slot 6 is in communication with the outlet 7, allowing toner to pass from the inner tube 3 through the slot 6 and the outlet 7 to the outside of the housing 2. On the contrary, when rotated the inner tube 3 to the close position, as shown in FIG. 2, the slot 6 is blocked from the outlet 7, and toner is stopped from passing to the outside of the toner cartridge 1.
In order to prevent leakage of toner through gaps between the inner tube 3 and the tubular portion 4 of the housing 2, sealing members 9 (for example, sponge members) may be fixedly fastened to the outside wall of the inner tube 3. However, because the inner tube 3 and the tubular portion 4 of the housing 2 are cylindrical members, the clearance between the outside wall of the inner tube 3 and the inside wall of the tubular portion 4 of the housing 2 maintains unchanged during rotary motion of the inner tube 3 relative to the housing 2, the sealing members 9 wear quickly with use, causing leakage of the toner, and toner may be accumulated in gaps between the sealing members 9 and the housing 2.